linguini1 opened a new pull request, #20197:
URL: https://github.com/apache/nuttx/pull/20197
## Summary
Implements the `pthread_sigqueue` function. **NOTE:** I am unsure if I have
to add this function to the syscall lookup and CSV like `pthread_sigmask`?
### docs/pthread: Document pthread_sigqueue
Documents the new implementation of pthread_sigqueue.
### sched/pthread: Implement pthread_sigqueue
Implements the pthread_sigqueue Linux extension to pthreads. Follows a
similar implementation to sigqueue, except targeting a specific thread through
nxsig_dispatch.
## Impact
Closes #20163.
Users can now queue signals to pthreads using this Linux extension interface.
## Testing
Tested using a custom application which uses a pthread to handle POSIX timer
events. When it is time to clean up the thread, `pthread_sigqueue` is used to
send `SIGABRT` which kills the thread.
Main program cancelling thread:
```c
cancelval.sival_ptr = NULL;
err = pthread_sigqueue(g_thread, THREAD_CANCEL_SIG, cancelval);
if (err)
{
syslog(LOG_ERR | LOG_USER,
"Couldn't send timer thread cancel signal: %d\n", err);
/* No point joining if we couldn't cancel. */
goto clean_topics;
}
err = pthread_join(g_thread, &threadret);
if (err)
{
syslog(LOG_ERR | LOG_USER, "Couldn't join to timer thread: %d\n",
err);
goto clean_topics;
}
syslog(LOG_INFO | LOG_USER, "Timer thread exited with status %d\n",
(int)threadret);
```
Thread logic:
```c
static void *timer_thread(void *arg)
{
int err;
int dep_fd = (int)arg;
sigset_t set;
siginfo_t info;
struct pyrochan_s *chan;
syslog(LOG_INFO | LOG_USER, "Timer thread started.\n");
/* Configure the set of signals we're waiting for (just timer signals) */
err = sigemptyset(&set);
if (err < 0)
{
syslog(LOG_ERR | LOG_USER, "Couldn't configure signal set: %d\n",
errno);
return (void *)(uintptr_t)errno;
}
err = sigaddset(&set, TIMER_SIG); /* We wait for timer signal */
if (err < 0)
{
syslog(LOG_ERR | LOG_USER, "Couldn't configure signal set: %d\n",
errno);
return (void *)(uintptr_t)errno;
}
/* We also allow a cancellation signal */
err = sigaddset(&set, THREAD_CANCEL_SIG);
if (err < 0)
{
syslog(LOG_ERR | LOG_USER, "Couldn't configure signal set: %d\n",
errno);
return (void *)(uintptr_t)errno;
}
/* We specifically unblock the timer signal from this thread's set of
* blocked signals.
*/
err = pthread_sigmask(SIG_UNBLOCK, &set, NULL);
if (err)
{
syslog(LOG_ERR | LOG_USER, "Couldn't unblock timer signal: %d\n", err);
return (void *)(uintptr_t)err;
}
/* We are waiting for the timer signal. */
for (;;)
{
/* Block until we receive a signal, with continue to re-block on
* spurious wake-ups.
*/
err = sigwaitinfo(&set, &info);
if (err < 0)
{
syslog(LOG_ERR | LOG_USER,
"Error while waiting for timer signal: %d", errno);
continue;
}
/* If this was a cancellation signal, stop execution and return */
if (info.si_signo == THREAD_CANCEL_SIG)
{
syslog(LOG_INFO | LOG_USER, "Timer thread cancelled.\n");
return 0;
}
/* Handle the timer expiration by deploying the channel and indicating
* the deployment event.
*/
chan = (struct pyrochan_s *)info.si_value.sival_ptr;
err = channel_fire(chan);
if (err == 0)
{
err = publish_deployment(dep_fd, chan->id);
/* Not really much to do if this fails; we continue so we can fire
* any other timer-based channels.
*/
}
/* Clean up the expired timer */
err = timer_delete(chan->timerid);
if (err < 0)
{
syslog(LOG_ERR | LOG_USER, "Couldn't clean up expired timer: %d\n",
errno);
}
}
return 0;
}
```
Log output:
```
pthread_sigqueue: tid=19 sig=10 value=0
nxsig_tcbdispatch: TCB=0x3fcb1cf8 pid=19 signo=10 code=1 value=0
Timer thread cancelled.
nx_pthread_exit: exit_value=0
pthread_completejoin: pid=19 exit_value=0
nxtask_exit: deployment pid=19,TCB=0x3fcb1cf8
pthread_join: Returning 0, exit_value 0
Timer thread exited with status 0
nxsig_tcbdispatch: TCB=0x3fca79b0 pid=7 signo=17 code=5 value=0 masked=NO
nxsig_tcbdispatch: Group 0x3fca7a90
nxtask_exit: deployment pid=16,TCB=0x3fcad620
Service 'deployment' pid 16 exited status 1
Removing service 'deployment' ...
```
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